---
name: "gen_packets"
section: "1"
platform: "linux"
package: "direwolf"
version: "1.7+dfsg-2+deb13u1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/gen_packets"
---

# gen\_packets(1)

Generate audio file for AX.25 frames.

## NAME

gen\_packets - Generate audio file for AX.25 frames.

## SYNOPSIS

**gen\_packets -o** *wav-file-out* \[ *options* \] \[ *text-file* \| - \]

*wav-file-out* is the result.  The -o option is required.

*text-file* may contain AX.25 packets in the standard monitoring format.  Use "-" to read from stdin.  If not specified, a default builtin message will be used.

## DESCRIPTION

**gen\_packets** is a test application which converts text to AX.25 audio for testing packet decoders.

It is very flexible allowing a wide range of audio sample rates, data speeds, and AFSK tones.  It will even generate the scrambled signals commonly used for 9600 baud operation.

## OPTIONS

- **-a** *n*

  Signal amplitude in range of 0-200%.  Default 50.  Note that 100% is corresponds to signal peaks of +/- 16383 so we have plenty of headroom to avoid saturation.

- **-b** *n*

  Bits / second for data.  Default is 1200.

- **-B** *n*

  Data rate in bits/sec for first channel.  Standard values are 300, 1200, 2400, 4800, 9600.

  300 bps defaults to AFSK tones of 1600 & 1800.

  1200 bps uses AFSK tones of 1200 & 2200.

  2400 bps uses QPSK based on V.26 standard.

  4800 bps uses 8PSK based on V.27 standard.

  9600 bps and up uses K9NG/G3RUH standard.

  EAS for Emergency Alert System (EAS) Specific Area Message Encoding (SAME).

- **-g**

  Force G3RUH modem regardless of data rate.

- **-j**

  2400 bps QPSK compatible with Dire Wolf \<= 1.5.

- **-J**

  2400 bps QPSK compatible with MFJ-2400.

- **-X** *n*

  1 to enable FX.25 transmit.  16, 32, 64 for specific number of check bytes.

- **-I** *n*

  Enable IL2P transmit.  n=1 is recommended.  0 uses weaker FEC.

- **-i** *n*

  Enable IL2P transmit, inverted polarity.  n=1 is recommended.  0 uses weaker FEC.

- **-m** *n*

  Mark frequency.  Default is 1200.

- **-s** *n*

  Space frequency.  Default is 2200.

- **-r** *n*

  Audio sample Rate.  Default is 44100.

- **-n** *n*

  Generate specified number of frames with increasing noise.  (For built-in message only.)

- **-o** *file*

  Send output to .wav file.

- **-8**

  8 bit audio rather than 16.

- **-2**

  2 channels of audio rather than 1.

- **-v***max\[,incr\]*

  Variable speed with specified maximum error and optional increment.

## EXAMPLES

**gen\_packets -o x.wav**

With all defaults, a built-in test message is generated with standard Bell 202 tones used for packet radio on ordinary VHF FM transceivers.

**gen\_packets -o x.wav -g -b 9600**

**gen\_packets -o x.wav -B 9600**

Both of these are equivalent.  "-B 9600" automatically selects scrambled baseband rather than AFSK.

**gen\_packets -o x.wav -m 1600 -s 1800 -b 300**

**gen\_packets -o x.wav -B 300**

Both of these generate 200 Hz shift, 300 baud, suitable for HF SSB transceiver.

**echo -n 'WB2OSZ\>WORLD:Hello, world!' \| gen\_packets -a 25 -o x.wav -**

**atest x.wav**

Read message from stdin and put quarter volume sound into the file x.wav.  Decode the sound file.

## SEE ALSO

More detailed information is in the PDF files at https://github.com/wb2osz/direwolf/tree/master/doc/.

Applications in this package: aclients, atest, cm108, decode\_aprs, direwolf, gen\_packets, kissutil, ll2utm, log2gpx, text2tt, tt2text, utm2ll